Conventionally, as disclosed in Patent Document 1 (JP 2006-247216A) for example, as this kind of electronic blood pressure monitor that uses an oscillometric method, there is known to be an electronic blood pressure monitor that retrieves a pulsewave signal that is superimposed on a cuff pressure signal and indicates a pulsewave at a measurement site (upper arm, etc.), while changing the pressure of a cuff attached to the measurement site, and calculates blood pressure values (including systolic blood pressure and diastolic blood pressure, the same applies hereinafter) using an envelope for a string of amplitudes (pulsewave amplitudes) of the pulsewave signal with a predetermined algorithm. Specifically, an envelope that is smoothed using interpolation or the like is created in order to eliminate blood pressure measurement error that occurs due to error in the pulsewave amplitude accompanying respiratory blood pressure variation and bodily movement. Then, threshold levels are set on a high-pressure side and a low-pressure side with respect to the maximum peak of the envelope, and the pressures at the points at which the envelope crosses the threshold levels are respectively calculated as the systolic blood pressure and the diastolic blood pressure.